Mixed signal circuits are commonly implemented in silicon technology across wider and wider regions of the spectrum. Baluns are useful to transform balanced signals into un-balanced signals and vice-versa. Broadband response, low loss, magnitude and phase imbalance are key performance specifications for the balun designer. However, it is a challenge to demonstrate reasonable performance particularly when implemented in a silicon technology.
On-chip integration of multiple functionalities can only be achieved in a conventional silicon process when low cost and large production volumes are required. The drive to higher and higher data rates is leading silicon technology towards the mm-wave spectrum providing the push for demonstrations of new circuit functionalities at higher and higher frequencies. In this context, the balun may be a key component to address when designing complex systems-on-a-chip design.
Baluns can be used to allow a balanced, differential signal to be transformed into an unbalanced, single-ended signal and vice versa. Differential signals experience less loss from a substrate than single-ended signals as they propagate through the circuit. This property is of particular interest when the frequency of operation is in the microwave and mm-wave region. Further, substrate loss is an additional challenge to consider when silicon is used for the integration of a high frequency system on a single chip.
Features and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.